• 10/30/2018
  • Public Content

Vectorization Basics for Intel® Architecture Processors

Intel® Architecture Processors provide performance acceleration using Single Instruction Multiple Data (SIMD) instruction sets, which include:
  • Intel® Streaming SIMD Extensions (Intel® SSE)
  • Intel® Advanced Vector Extensions (Intel® AVX) instructions
  • Intel® Advanced Vector Extensions 2 (Intel® AVX2) instructions
  • Intel® Advanced Vector Extensions 512 (Intel® AVX-512) Foundation instructions, Intel® AVX-512 Conflict Detection instructions, Intel® AVX-512 Doubleword and Quadword instructions, Intel® AVX-512 Byte and Word instructions, and Intel® AVX-512 Vector Length Extensions for Intel® processors
By processing multiple data elements in a single instruction, these ISA extensions enable data parallelism.
When using SIMD instructions, vector registers can store a group of data elements of the same data type, such as
. The number of data elements that fit in one register depends on the microarchitecture and on the data type width: for example, in case CPU supports vector register width 512 bits, each vector (ZMM) register can store sixteen float numbers, sixteen 32-bit integer numbers, and so on.
When using the SPMD technique, the Intel® OpenCL™ implementation can map the work items to the hardware according to one of the following:
  • Scalar code, when work-items execute one-by-one
  • SIMD elements, when several work-items fit into one register to run simultaneously
The Intel® SDK for OpenCL™ Applications contains an implicit vectorization module, which implements the second method. Depending on the kernel code, this operation might have some limitations. If the vectorization module optimization is disabled, the Intel SDK for OpenCL Applications uses the first method.

See Also

Product and Performance Information


Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

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